I know it's not a popular opinion, but I do not like the Hydor I have. It's the 750gph powerhead in my 29g tank. It's flow is good but it's quirky. They ALL have problems with not producing flow sometimes...the turn the plug around fix works sometimes but not always. It is a pain in the ass a lot of the time. Also, the thing is HUGE. It is unnecessary big.
I bought a JBJ Oceanstream 500gph pump about 5 months ago and it is FANTASTIC. It always works no matter what. IT also has the magnetic holds just like hydor but its profile is like 1/2 the size. The only disadvantage is a decreased ability to control flow direction but imo its worth it. I have both in my tank and I'm still considering whether I want another oceanstream and get the jbj wavemaker system or just spend the $$ and get the vortech.
Either way, I can't recommend the hydor. It's just not that good in my experience.